Spending in the referendum battle over Central Maine Power's transmission corridor has exceeded $60 million so far this year.
The spending is led by CMP, which pumped roughly $8.6 million into two ballot question committees over the past three months to bring its expenditures to nearly $20 million for the year.
Maine's largest utility is trying to defeat Question 1, which if approved by voters, would yank the lease for the 145-mile transmission project that's part of a deal between the company and the state of Massachusetts.
Hydro-Quebec, the energy supplier for the project, dumped another $4.9 million into its campaign in the months after Gov. Janet Mills vetoed a bill that would have barred electioneering by companies owned by foreign governments.
The anti-corridor spending is led by Mainers for Local Power, which is funded by out-of-state energy companies Calpine and NextEra.
That group spent $7 million in three months, a significant increase over the rest of the year.